The MPPT Control Strategy Of Small Scale Wind Power Generation System

Due to its clean and renewable characters, Wind energy has developed rapidly in recent years and ranks as one of the most promising renewable energy resource. Wind power generating system is complicated for wind energy has the properties of both randomness and uncertainty. Small scale wind power generation system with its low cost, simple control, occupies its important proportion.At first, this paper introduces the application situation of wind power generation, and makes a basic overview of the work principle, subassemblies and sorts of grid-connected wind turbine. After comparing three converter topologies of the permanent magnet synchronous generating system, a kind of small scale wind power generating system, which is composed of wind turbine with fixed pitch, permanent magnet synchronous generator, rectifying bridge, boost chopper and inverter, is suggested in this paper. Different from the speed-current double closed-loop and voltage-current double closed-loop method, we have adopted a power control method which uses the relationship between speed and current. This paper details the method, and makes a simulation in the MATLAB/SIMULINK environment. The simulation is focused on the effect of power control when wind speed changes. According to simulation results, we make a appropriate correction on the relationship table. After correction, we can make the wind turbine send out the maximum power, and the DC load track the maximum power. Finally, we do a preliminary description of the method which uses unloading device to limit the maximum power.